Battery charging system



Feb. 19, 1946. 'c. T. CORNING BATTERY CHARGING SYSTEM Filed Dec. 5, 1942 TOR.

BY A? Jfd ATTO

Patented Feb; is, was

UNITED STATES PATENT osslcs 2 Claims. (Cl. 320-39) This. invention relates to battery charging equipment and has for its object to enable batteries oi diflerent voltage to'be charged at substantially the same charging current.

Btoragebatteries are ordinarily charged from an alternating current source of supply by means of rectifying equipment. The output of the charsins quipment is usually designed to provide the desired charging rate oi current tor a battery of a predetermined voltage and ii a battery of a diiierent voltage is to be charged the equipment may be provided with adjusting means for manually adjusting the equipment to maintain substantially the same charging rate in spite of the diiierence in battery voltage.

In some instances it is desirable that the equipment shall provide substantially the same charging rate regardless of dii'i'erences in the voltages of the batteries being charged, and without the necessity for manually adjusting 'or adapting the charging equipment to the diflerent battery volt ages. This is carriedout according to the present invention by the provision oi a voltage operated relay across the battery terminals adapted to respond diiIerently to the batteries of diiIerent voltages. The operation of the relay is used to adjust the charging equipment in accordance with the battery voltage. The invention will be better understood from the following detailed description and the accompanying drawing which illustrates a battery charging equipment in accordance with this invention.

The equipment is shown operated from a 3- phaseAQmainsshownbywires Llandl connected to a terminal block 4 which is connected by wires I, 8 and I through a relay-operated contactor I to the respective free ends of the star-connected primary windings 8, I and ll of a power transformer. {I'he relay-operated 40 ll of the primary windings oi the transformer,

contactor-or switch 8 is closed by closure of manually operated switch ill which energizes the windingoirelaylirommainwlresiandJJo pull in the armature oi the relay. Each primary winding is provided with a tap I, III and ii respectively. The connection from the mains to the star-connected primaries is made through the armature contacts of a relay I! so that when the relay is de-energized the full primaries are connected in circuit over contacts lI-i l, lt-lt', and lB-li'. When the relay is energized its armature is pulled down and the only parts of the primary windings in circuit are those between the central star connection and the taps, these connections being made over the lower sets of contacts IHII', ill|' and tel-ll.

The secondary oi the transformer is composed of three delta-connected secondary windings II, and It, the output leads :2, 2t, 24 from which are connected in' a conventional manner to a bridge-connected rectifier 25. The individual rectiiiers It, 21, 2., II, and 3| 0! the bridge may be oi the well-known selenium or copper oxide type. One of the D. C. output leads 82 of the rectifier is connected to the output terminal 33 and the other output lead 34 is connected through an overload relay winding 35 and then through lead 38 to the other output terminal (ll. Relay II is a protective device which opens the. circuit through the winding of relay I and is consequently shuts oil the power supply to the transformer when there is an overload through the battery.

There is connected across the battery charger output terminals II and 31 the winding of a volt- 20 age operated relay II, the armature of which opens or closes the contacts 39 and 40 of a circult comprising lead ll, the winding of relay l2,

lead I, main wire I, main wire 2 and lead 2.-

.Relay is is adjusted so that when a low voltage 25 battery, for example a six volt battery, is conso upper sets of contacts of relay I! are in circuit.

When a higher voltage-battery, for example of twelve volts, is connected across output terminals 31 and 31, relay is is sufilciently energized to pull in its armature, closing contacts 39 and ill and 85 energizing relay l2. The armature of relay I2 is consequently pulled into open its upper sets oi contacts and close its lower sets of contacts, namely contacts l6, i6, i1, I1, and l8. It. This connects the A. C. power to the taps 9', l0 and thereby raising the voltage at the secondaries and consequently across the battery. The taps are so placed in the primary windings that the rise in voltage at the secondary is about sufllcient to compensate for the higher voltage battery so that the charging rate through the battery isabout the same regardless oi whether the lower voltage battery or the higher voltage battery is connected.

In the usual case, the two batteriesoi. different however, that batteries of different voltages may thus be; provided for and even three or more diiferent voltages may be provided for. Where more than two diiIerent voltages are to be provided for,

there can be connected across the D. C. output terminals a correspondingly increased number of voltage operated relays, each being connected to a relay such as I! to connect with a different tap on the primary. Ii! desired, the relay I! could be made to operate on secondary taps instead oi primary taps to compensate for the difierent battery voltages. I

It will be understood that the invention is not limited to a three-phase system as illustrated but might be used with other kinds of supply lines.

It will be seen that by this invention there is provided a battery charging system which automatically accepts batteries of different voltages and provides them with substantially the same charging current independent of their voltages.

What is claimed is:

1. Battery charging apparatus comprising means for providing charging current including a source of direct current of two different voltages tions normally connected to the lower voltage from said source; and means for automatically connecting to said terminals the voltage from said source corresponding to the voltage rating of a battery of either type connected to the terminals, comprising a voltage responsive electromagnetic device energized by a minimum voltage between said voltage ratings, and switch means actuated by said device ior connecting the higher voltage from said source to said terminals.

2. Battery charging apparatus as set forth in claim 1 in which the source of direct current comprises a source of alternating current, a transformer and a rectifier connected in series, and taps on the transformer arranged to provide said different voltages at the rectifier output; and in which the switch means comprises means for selectively connecting said taps in circuit between the source 01' alternating current and the recti- CHARLES T. CORNING. 

